Construction Water – Why It Should Matter
Water is among the most vital elements in construction, but many people overlook its quality. During construction, water is essential for mortar preparation, cement concrete mixing, and curing operations, among other things. The toughness of mortar and cement materials for construction projects is greatly influenced by the quantity and quality of water.
Quality of water
In general, the quality of construction water is comparable to that of drinking water. This is to guarantee that water is relatively free of contaminants such as suspended particulates, organic matter, and dissolved salts, all of which can negatively influence the qualities of concrete, including setting, stiffening, hardness, longevity, pit value, and so on.
The water used during mixing and curing must be free of harmful chemicals such as alkalis, acids, lubricants, sodium, sugar, organic materials, plant growth, and other substances that could harm bricks, stone, concrete, or steel. In most cases, potable water is sufficient for mixing. Water should have a pH value of at least 6.
Quantity of water
Water is an essential ingredient in mortar and concrete. Water quantity and quality have a significant impact on mortar and cement concrete strength.
Many times it has been noted that even employing the greatest raw materials, cement, and tested water, concrete fails to deliver the desired outcomes.
Engineers and contractors believe there is a problem with cement, but they fail to examine the water to cement ratio or the amount of water blended.
When water is mixed with cement in mortar, it generates a binding paste that fills small spaces in the sand. This results in a tight bond between the sand particles and the cement.
The spaces generated between the sand and coarse aggregate in cement concrete are filled with the paste, resulting in a cohesive substance or concrete.
When making mortar or concrete, the required amount of water is utilized, but in practice, more water is added to render the mix workable.
This is a terrible practice since it weakens the cement paste's strength. Extra water also degrades the adhesive's performance.
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Disadvantages of increasing quantity of water in concrete
- Water takes up space in the sand and evaporates, leaving gaps. Furthermore, the number of water spaces will increase, reducing the density, strength, and endurance of concrete.
- Extra water causes a mixture of excess cement paste and water to float on the surface when concrete has more water mixed in it. In the case of water tanks and dams, this material generates a thin coating of powdery material on the surface, which prevents proper bonding with the new layer of cement concrete. This will have an impact on the concrete's strength.
- The cement slurry begins to emerge from the cement concrete mix as more water is added. Shuttering joints allow excess slurry generated by cement and water to escape.
- If more water is utilized, appropriate compaction is lost, resulting in bleeding, huge voids, and shrinking, as well as decreased durability and strength.
- If more water is added to cement mortar, the problem of material segregation arises during the laying process. As a result, the coarse aggregate and the cement paste might separate.
Testing The Water To Be Used
- Limit of acidity - It should not take over 2m of 0.1 normal sodium hydroxide or Caustic soda to neutralize a 200 ml volume of water. In general, the pH of the water should not be less than 6.
- Limit of alkalinity - With methyl orange as that indicator and 10ml of 0.1 normal hydrochloric acid or HCL should be enough to neutralize 200 ml of sample.
It is a popular belief in the construction industry that water suitable for human consumption can be used to mix concrete and cure work. However, before using the water in building, it must be checked. When you're spending a lot of money on building, a limited fraction invested on water testing shouldn't be overlooked. Water that has been tested or treated should be utilized to strengthen the strength of the concrete and extend the life of the building.
Water for Concrete Mixtures
Regular water reducers and high-priced water reducers are chemical admixtures that can be used in concrete. The water reducers will raise the slump and smoothness of the concrete without adding extra water and all of its negative effects, depending on the needed slump or consistency.
For the same water-cement ratio, the water reducer additive enhances the workability of concrete/mortar.
Workability Of Concrete
The ease with which freshly mixed concrete may be mixed, put, cemented, and finished with little loss of homogeneity is referred to as workability.
The workability of a concrete admixture is an important issue to consider while testing it. Rapid loss of workability happens within the first few minutes of mixing concrete, followed by gradual loss of workability over the next 15 to 60 minutes.
These admixtures extend the time it takes for concrete to cure by 2 to 6 hours, allowing it to be vibrated during that time.
This is highly relevant in hot weather or when the nature of the job necessitates a delay between the positioning of consecutive concrete layers.
